Fabrication and characterization of a hydroxyapatite-methylcellulose composite coating on the surface of AZ31 magnesium alloy

Magnesium alloys are attracting attention as materials for use in biological applications. In this work, Ca(OH)2 and Ca(H2PO4)2·H2O are used as raw materials, and methylcellulose is used as an additive, to prepare a hydroxyapatite-methylcellulose composite coating on the surface of AZ31 magnesium alloy using a sol-gel technique. Phase analysis, a surface morphology study, and cross-section and microstructure characterization of the hydroxyapatite-methylcellulose composite coating are presented. Potentiodynamic polarization curves and corrosion morphologies of the coating are also presented. The results indicate that the thickness of the hydroxyapatite-methylcellulose composite coating is approximately 60 μm and the composite coating could improve the biodegradation property of AZ31 magnesium alloy effectively.